Adsorbent carbon, particularly activated carbon, is used extensively for a variety of purposes many of which depend to a considerable extent on the large surface area and surface activity of the carbon particles. Carbon therefore is used in many filter applications. For example, carbon filters are used in water filtration systems to remove dangerous organic compounds that are present in drinking water, as disclosed in U.S. Pat. No. 4,561,976.
Wojcik and Karpinski described, in Chemia Stosowana XII, 2, 351 (1978) a process of modifying carbons by treating activated carbon with trimethylchlorosilane and dimethylsulfoxide. The modified carbon displayed lower adsorption properties for water and ethanol vapour. The reduction of adsorption properties with respect to water vapour was larger than with respect to ethanol.
In the present invention, chlorinated silanes are avoided. If chlorinated silanes are used hydrogen chloride (HCl) will be produced during the silylating process. It is thus possible that the silylated carbon produced also contains trapped HCl, that may then leach out of the treated charcoal and cause problems such as corrosion.